Roniciclib (BAY1000394) is a pan-cyclin-dependent kinase inhibitor that has been developed for treatment in small cell lung carcinoma and solid tumors. Roniciclib targets certain key proteins that are essential for the survival of cancer cells, resulting in decreased tumor growth. Phase I studies to evaluate the safety, tolerability and pharmacokinetics of roniciclib have been completed successfully. In phase II studies, roniciclib was found to be well tolerated and showed promising efficacy when combined with chemotherapy in small cell lung carcinoma patients. However, due to an observed safety signal (treatment-emergent adverse events) in one phase II study, other clinical trials have been discontinued and further development of roniciclib was terminated.